Only evil wizards can cast this spell, and the Red Wizards of Thay do not teach it to outsiders.
Casting the spell involves a series of magical rituals intended to turn a normal human (of up to 3rd level) into a maddened, murderous creature.
The victim must be bound and helpless for the spell to work.
After the casting time is completed, the victim must make a Will save or be transformed into a chosen one under the control of its creator.